Why is my "Referrals" count = 0 ?

[Lumina]

I remember, a long time ago, I had 1 referral on this board :
http://www2.vbulletin.com/forum/showthread.php?t=67376&highlight=referrals

Why do I have 0 now ?
http://www2.vbulletin.com/forum/member.php?u=21174